Control device



11111626, c Q FARMER 2,379,289

CONTROL DEVIC E Filed Sept 29, 1942 Sheets-Sheet l INVENTOR 01,3116: ClTJmTMzT BY I ATTORNEY C. C. FARMER CONTROL DEVICE June 26, 1945.

Filed Sept. 29, 1942 5 Sheets-Sheet 2 llqrll INVENTOR ClydeCFavmer BY wqw -ATTORN EY June 26, 1945. c. c. FARMER 2,379,289

CONTROL DEVI CE INVENTOR $1) deCFdPmen B ATTORNEY P otented June 26, 1945 CONTROL DEVICE Clyde 0. Farmer, Pittsburgh, Pa., assignor to The Westinghouse Air Brake Company, Wilmerding, Pa., a corporation of Pennsylvania Application September 29, 1942, Serial No. 460,068

23 Claims.

This invention relates to control devices operatively responsive to the rate of acceleration or deceleration of a rotary element, such as 9. ve-

hicle wheel, and suited for any desired indicating or control purpose.

The control device comprising my present invention is of the so-called rotary inertia type having a fly-wheel rotatively driven according to the speed of rotation of a rotary shaft and coupled to the shaft in a manner to permit the flywheel to over-run or under-run the shaft in response to deceleration or acceleration, respectively, of the shaft. Devices of this character are well-known and have been employed for various indicating or control purposes, such as the detection of the slipping condition of a vehicle wheel and the control of the brakes associated with the vehicle wheel in a manner to prevent the sliding of the vehicle wheel.

It is a well known fact that a slipping vehicle wheel, such as a railway car wheel, rotatively decelerates or accelerates at an abnormally rapid rate inresponse to a brake application or a propulsion torque respectively, applied thereto and suflicient to exceed. the adhesion between the wheel and rail or road surface. The rotative deceleration or acceleration of the vehicle wheel at the rate exceeding a certain rate, such as ten miles per hour per second, is thus positive indication 01' the slipping condition of the wheel.

The terms sliding condition and "slipping condition as employed herein are not synonymous. The term sliding condition refers only to the locked or non-rotative condition of the vehicle wheel whereas the term slipping condition" refers to the rotation of the vehicle wheel at a speed different from that corresponding to vehicle speed at a given instant.

In my prior Patent 2,184,550 there is disclosed a rotary inertia device in which the fly-wheel is connected to the driving shaft through a clutch device of the friction type, the clutch device being such as to permit the fiy-wheel to over-run the driving shaft when the rotative deceleration of the driving shaft exceeds a certain rate. The device in this patent, moreover, comprises an arrangement effective in response to the relative rotative movement of the fly-wheel and the driving shaft for partially releasing the effective coupling force of the clutch whereby a braking effect is exerted on the fly-wheel so that it rotatively decelerates at a rate not exceeding the rate of retardation of the vehicle. In such case, therefore, the rotation of the fly-wheel relative to the shaft continues until such time as the shaft is restored substantially to the rotational speed of the fly-wheel.

The device functions in a fluid pressure brake control system to initiate a reduction in the degree of application of the brakes associated with a slipping wheel when the slipping begins and continues such reduction until such time that the slipping wheel is restored substantially to vehicle speed.

It is an object of my present invention to provide a control device of the rotary inertia type having a clutch for establishing a driving connection between the fly-wheel and a driving shaft and characterized by a, novel arrangement for controlling the clutch means whenever the driving shaft changes its rotational speed at a rate exceeding a certain rate for maintaining a continued operative response of the device as long as the driving shaft rotates at a speed substantially diflferent from that of the fly-wheel.

More specifically, it is the object of my invention to provide a control device of the type indicated in the foregoing object and characterized by an arrangement including opposing centrifuges carried by the fly-wheel and the driving shaft respectively. whereby to control the clutch means between the fiy-wheel and the driving shaft and thus the operative response of the device.

It is another object of my invention to provide a vehicle brake control system employing the novel type of control device mentioned in the foregoing objects for the purpose of initiating a reduction in the degree 01 application of the brake associated with a wheel that starts to slip and continuing such reduction automatically throughout the slipping interval.

The above objects, and other objects of my invention which will be made apparent hereinafter,

are attained in apparatus subsequently to be described and shown in the accompanying drawings wherein Figure 1 is a diagrammatic view, showing one embodiment of my invention employed in connection with the wheels of a railway vehicle or car for the purpose of controlling the brakes associated with the wheels.

Figures 2 and 3 are sectional views, taken on the lines 2-2 and 3-3 respectively of Figure 1, showing further details of construction of the control device, and

Figure 4 is a fragmental view, showing a second embodiment of my invention.

Description first embodiment Referring to Figures 1, 2, and 3, showing the first embodiment of my invention, the control device shown therein comprises essentially a tubular drive shaft l2 Journaled in longitudinally spaced bearing pedestals i3 that are attached to a base It; a fly-wheel l3 rotatlvely mounted on the shaft it between the pedestals l3; a clutch device It for coupling the fly-wheel to the drive shaft l2; a clutch release magnet device I'I carried by one of the pedestals l3; a centrifuge device |3 carried by the shaft l2 and rotatable at all times according to the speed of the shaft; and a centrifuge device i3 carried by the fly-wheel i3 and rotatable at all times in accordance with the rotational speed of the fly-wheel.

Shaft I! may be driven through any suitable connection by rotation of a rotary member, the rate of change of speed of which is to be registered or detected. As shown, the shaft I! has a bevel-pinion 2| fixed thereon that meshes with a corresponding bevel-gear 22 fixed on a shaft 23. The shaft 23 may be coupled directly to the axle of a wheel and axle unit 23 of a railway car and is preferably flexible in character to permit mounting of the control device II on the body of the car.

The control device ll may be provided, as shown, with a suitable housing comprising two sheet metal end members 33 and a U-shaped casing 23 of sheet metal, the casing being secured as by screw 21 to the end members and to the base It.

Considering the parts of the control device II in further detail, the clutch device l3 comprises a cup-shaped spider member 3| of non-magnetic material, such as brass or aluminum, having a central hub 32 which is slidably keyed or splined to the drive shaft I! so as to permit the axial movement of the spider member 3| with respect to the shaft I 2.

A roller 33 is carried on a pin 33 that is fixed radially to the cylindrical wall of spider member 3|. The 'roller 33 engages in a shallow V- shaped notch 31 formed in an annular cam 33 at one side of the web of ily-wheel l3. The roller 33 is yieldlngl held in the notch 31 by a coil spring 39, co tained within the tubular, bore 33 of the drive shaft I2, which is efiective to urge the spider member 3| in the left-hand direction. A suitable stop-nut 3| and lock-nut 42 are screwed into the open end of the shaft I! to form a support for one end of the spring. the other end of the spring acting on a piston 35 slidably in the bore 43 0f the shaft ii. The piston 45 has a stem 46 that extendslongitudinally through the bore 43 and projects out of the lefthand end of the bore 33 for a purpose presently to be described. The spider member 3| is connected to the stem 33 adjacent piston 33 by a screw 41 that projects through a longitudinal slot 43 in the wall of the shaft i2 and into a suitable hole in the stem 43.

Secured to the cylindrical wall of pider mem ber 3| at a point diametrically opposite to the roller 33 is a counter-weight 33 that provides dynamic balance for the spider member II. A brake shoe 33, in the form of a flat. steel spring having a friction element thereon, is secured to the spider member 3| as by the same screw that attaches the counter-weight 33, so as to eng e the inner surface of the annular cam 33 to exert a braking effect on the fly-wheel II, for a purpose hereinafter explained. when the fly-wheel rotates relative to the shaft I 3.

The hub of the fly-wheel I3 is fixed for rotation on the shaft I! in a certain axial position, as by snap rings 3| at opposite ends of the hub. A thrust bearing 32 is preferably provided between one of the snap rings and the hub of the fly-wheel to prevent undue friction between the hub of the fly-wheel and the snap ring which might otherwise be produced by the biasing force of spring 33 acting through the clutch spider member 3| and roller 33 on the ily-wheei II.

A ring 33 of magnetic material is suitably secured to the spider member 3|, a by one or more screws 36, in concentric relation to the shaft I! and functions in cooperation with the clutch release magnet device |l in the manner mesently to be described.

The spring 33 is so designed in relation to the dimensions and weight of the fly-wheel II as to maintain the fly-wheel in coupled relation to the shaft I: as long as the rate of rotative deceleration or acceleration of the shaft I! does not exceed a certain rate. Thus when the shaft i3 is driven according to the speed of the wheel unit 24, the fly-wheel is maintained in coupled relation to the shaft I! as long as the wheels do not rotatively decelerate or accelerate at a rate exceeding ten miles per hour per second.

When the shaft I2 rotatively accelerates or decelerates at a rate exceeding the predetermined rate, the inertia of the fly-wheel I3 is effective to overcome the force of the spring 33 and thus to cause the roller 33 to ride out of the notch 31 to the outer surface of annular cam 33, thereby causing the spider member 3| to be shifted axially in the right-hand direction in opposition to the force of the pring 33.

The piston 43 and its stem 43 is thus correspondingly shifted axially in the right-hand direction to effect closing of a switch device 31. The switch device 31 is of the telephone type and may comprise two flexible contact fingers having cooperating contacts and carried in a suitable insulating member 33 attached to the adjacent pedestal I3. One of the contact nngers of the switch device 51 is longer than the other and extends upwardly toward the stem l3 so as to be engaged by a collar 33 carried on the stem 45. The contact fingers of the switch 31 are normally separated and are engaged only in response to the bending of the long contact linger in the right-hand direction in response to the shifting of the stem 43 of the piston 33.

The outer end of the stem 43 is supported in a suitable guide bushing 3| attached to the outer end of a sleeve 82 that is axially siidable in the bore 43 of the shaft It. The guide bushing 3| has an annular groove 63 therein, in which is received the end of a contact finger of a switch device 33, the two contact fingers of which are supported by the insulating base 53. The contact fingers of switch 33 are normally separated and are operated into contact with each other only in response to the movement of the sleeve 62 in the right-hand direction under the control of the two centrifuge devices i3 and H in the manner hereinafter to be described.

The clutch release magnet device |I comprises an annular base 31. of non-magnetic material such" as brass, aluminum, or molded material. having a central opening 33 through whichthe shaft l3 extends, the member being secured to two or more bosses 33 projecting laterally from the right-hand bearing pedestal i3.

As shown in Figure 3, the clutch release magnet device I! further comprises a plurality of electro-magnet windings ll, illustrated as four in number, each winding surrounding a magnetic core element in the form of a securing bolt 12 screwed into one of two arcuate members I3 of magnetic material that are, in turn, attached by screws I4 to the non-magnetic'base 81;"

As will be seen in Figure3, two of the electromagnet windings H are attached by bolts 12 in spaced relation to one of the arcuate magnetic members I3 and the other two windings II are similarly attached to the other arcuate magnet member 13.

The windings H are connected in series relation by a wire N in such a manner as to cause the heads of the bolts I2 to act as pole-pieces of opposite polarity, alternately. Thus, two U- shaped electro-magnets are provided in the magnet device IT.

The opposite ends of the wire I. are connected to suitable stud bolts or terminal posts It and I! respectively, that are secured in spaced relation in an insulating cover II. The insulating cover is in the form of. a hollow cylinder disposed in concentric relation to the shaft I 2 and having at one end a radial flange secured along with base I, by screws If, to the bosses is on pedestal It.

The magnetic attraction exerted by the polepieces or bolt heads of the bolts I! of the magnet device I! for the magnetic ring I! on the clutch spider member II is inen'ective to move the spider member i l against the opposition of the spring 39 as long as the roller 33 engages in the notch 31 on the fly-wheel Ii. when the spider member II is shifted axially in the righthand direction with respect to the shaft II due to the fly-wheel I! over-running or under-running shaft II. the ring I! is brought into close proximity to the heads of the bolts I! so as to render the magnetic attraction of the magnet device I? sufficient to maintain spider member if in displaced axial position with the roller 33 out of contact with the outer surface of the cam 38 on the fly-wheel II. It will be understood that the ring 55 does not engage the heads of the bolts 12 but remains out of engagement therewith, thereby avoiding any frictional contact between the ring and the stationary bolt heads.

The manner in which the windings H of magnet device I! are energized so as to be effective to maintain the clutch spider member 3| in disengaging position with respect to the fly-wheel l5 will be explained presently. I

The centrifug device l8 comprisesa supporting member having a hub portion and two diametrically opposite radially extending arms provided with yokes 84 at the outer ends thereof. Pivotally carried on av suitable pin 85 in each of the yokes 84 is a bell-crank lever 86, one arm of which is short and the other of which is long. Fixed on the outer end of the short arm of each bell-crank lever 86 is a weight in the form of a solid cylinder 81. The outer end of the long arm of each of the bell-crank levers 86 is formed in the shape of a ball 88, the balls on the two levers l6 engaging in an annular groove '9 formed in a collar 9! slidably mounted on the shaft II.

The sliding collar 9| is connected by a screw or pin 93 to the sliding sleeve 62, the pin 93 extending through an axially extending slot 94 in the wall of the shaft I! which permits axial movement of the collar and sleeve.

Centrifuge is, carried by th fly-wheel i5 is similar to centrifuge I. and comprises a plurality of bell-crank levers It eachpivoted on a pin I! supported between suitable bracket II attached to the web of the fly-wheel II. A cylindrical weight I! is fixed on the outer end of the short arm of each of the above levers II and the outer end of the long arm of these lev rs is formed as a ball 88. The balls ll of the bellcrank levers It of the centrifuge l9 engage in an annular groove It in sliding collar 8| located in axially spaced relation to the groove '9.

The pins on which the bell crank levers of the two centrifuges II and I! are supported are at exactly the same radial distance fromtheinris of the rotation of the shaft l2 and the weight of the cylindrical weights ll of the two centrifuges are identical. It will thus be seen that as long as the fly-wheel l5 and the shaft l2 rotate at the same speed. the centrifugal forces of the weights ll of the two centrifuges are exerted of the sliding collar 9| in opposite directions and, being of equal intensity, the sliding collar 8| remains unmoved. Whenever the fly-wheel rotates at a different speed than the shaft II, for example at a faster speed than the shaft II, the forces exerted on the sliding collar ll are unbalanced and the collar 9| is accordingly shifted in an axial direction corresponding to the predominating centrifugal force of one or the other of the centrifuges. 7

When the sliding collar 9! is shifted in a righthand direction in response to the predominating centrifugal force exerted by the centrifuge IS, the sleeve 62 is correspondingly shifted to effect closing of the switch 64.

The switch 64 controls the circuit of the magnet windings II, of the magnet device II. This circuit will be traced in detail hereinafter in connection with an assumed operation, but it may be here briefly stated that the differential in the rotational speeds of the fly-wheel l5 and the shaft 12 produced when the clutch device I6 is operated to disengage the fly-wheel is from the shaft is such as to cause substantiallyinstantaneous closure of the switch 64 and consequent energization of the magnet windings of the magnet device ll, thus renderin the magnet device I! effective to maintain the spider member if of the clutch device It in its disconnecting position.

While my control device H is suited for various applications. wherein it is desired to register a. predetermined rate of rotative acceleration or deceleration of a rotary element, I have for purpose of illustration shown it in connection with a fluid pressure brake control equipment'associated with the wheels of a railway car. For purposes of the present application, I have illustrated a simple straight-air type of fluid pressure brake equipment comprising a train pipe IM, hereinafter designated the straight-air pipe; a brake valve I02 of the self-lapping type for controlling the pressure in the straight-air pipe "I; a source of fluid under pressure such as a reservoir I03 that is normally charged with fluid under pressure as by a fluid compressor not shown; a brake cylinder IN to which fluid un der pressure is supplied from the straight-air pipe ll! through a branch pipe I05 in which is interposed a magnet valve device "it; and fluid pressure operated switch It! connected to the straight-air pipe I ll through a branchpipe I08. The brake valve I02 may be of any well-known self-lapping type, such as that disclosed and cla med in Patent No. 2,042,112 to Ewing K. Lynn and Rankin J. Bush. Briefly, the brake valve It! may comprise an operating handle "2a fixed on pressure to be supplied mechanism of the brake valve the end ofa rotary operating shaft, the rotation of which causes operation of suitable supply and release valves of the self-lappin type. With the brake valve handle I02a in its normal or brake release position, the valve mechanism oi the brake valve is conditioned to cause fluid under pressure to be exhausted to atmosphere from the straight-air pipe Il I00 and an exhaust port and pipe I I0. when the brake valve handle I02a is displaced in a horizontal plane out of its normal position into its so-called application zone, the valve mechanism of the brake valve operates to cause fluid under from the reservoir I 03 to the straight-air pipe Ill. The nature of the valve mechanism of the brake valve is such as to cause a lapping or cutting-off of the supply of fluid under pressure to the straight-air pipe IOI as the pressure established in the straight-air pipe increases above a certain value corresponding to the degree of displacement of the brake valve handle I02a out of its normal position. The pressure established in the straight-air pipe I" is, therefore, substantially proportional to the degree of displacement of the brake valve handle I020 out oL its normal or brake release position.

If the pressure in the straight-air pipe IOI reduces for any reason, such as leakage, the valve I02 operates automatically to continue the supply 01 fluid under pressure to the straight-air pipe IN to maintain a pressure therein corresponding to the position of the brake valve handle I02a. This pressuremaintaining feature of the brake valve will be referred to hereinafter in connection with an assumed operation;

The magnet valve device I 00 is of standard and comprises a double-beat valve III urged to an upper seated position by a coil sprin H2 and actuated in opposition to the spring II2 to a lower seated position in response to energization of a magnet winding or solenoid III actin: through the medium of a plunger I;

In its upper seated position, in which it is shown, the double-beat valve III establishes communication through the branch pipe I05 from the straight-air pipe III to the brakecylin Ill. thus permitting fluid under pressure to be supplied to the brake cylinder and released therefrom under the control of the brake valve I02.

In the lower seated position of valve III, communication through the branch pipe I 05 is closed and a connection established between the brake cylinder Ill and a chamber II! which is constantly connected to atmosphere through a port Iii, thereby causing fluid under pressure to be rapidly released from the brake cylinder I04 independently of the fluid pressure in the straight-air pipe III.

It will be understood that the brake cylinder I00 is of the type that is effective to cause application of the brakes in response to the supply of fluid under pressure thereto and release of the brakes in response to the venting of fluid under pressure therefrom. It will thus be seen that energization of the magnet winding IIO of the magnet valve device I00 will cause a release of the typ brakes associated with the car wheels independ-- ently of the brakes associated with other car wheels, not shown, cording to the fluid The pressure-operated switch I01 may be of pressure in the straight-air but similarly controlled acaavamsa through a branch pipe the pressure switch any suitable type responsive to variations of pressure in the straight-air pipe IM to opposite sides of a certain critical pressure. Thus, for purposes of the present invention, it will be assumed that I01 is actuated to its closed position and maintained therein only so long as the pressure in the straight-air pipe Ill exceeds a certain low pressure such as flve pounds per square inch and is restored to its open position in response to the reduction of pressure in the straight-air pipe IOI below flve pounds per square inch.

Operation of first embodiment Let it be assumed that a railway car, equipped as shown in Figure 1, is traveling under power and that the operator desires to effect an application of the brakes to bring the car to a stop. To do so the operator first cuts-oil! the propulsion power and then shifts the brake valve handle I02a from its brake release position into its application zone an amount determined according to the desired degree ofv brake application. Fluid under pressure is accordingly supplied to charge the straight-air pipe IM to a corresponding pressure, such as fifty pounds per square inch, fluid at the pressure in the straight-air pipe being supplied through branch pipe I05 to brake cylinder I04 to cause application of the brakes associated with the car wheels to a corresponding degree.

As long as the car wheels do not slip, no variation in the degree of application of the brakes occurs, aside from variations caused by variations in the coemcient of friction between the brake the operation of the brake valve I02 to vary the pressure in the straight-air pipe IOI.

Let it be assumed, however, that when the brakes are applied, the car wheels shown in the drawings begin to slip. As previously stated, the car wheels rotatively decelerate at an abnormally rapid rate during a slipping condition. In such case, therefore, the inertia of the fly-wheel I! of the control device I I overcomes the force of the spring 39 and causes the axial shifting of the spider member SI of the clutch device I6 so as to close the switch 51.

Switch 51 is effective, when closed, to establish a circuit for energizing the magnet winding I I3 of the magnet valve device I06. The circuit extends from the positive terminal of a storage battery IIO, by way of a wire IIQ, switch 51, a wire I20 including the .magnet winding H3 of the magnet valve device I00, a wire I2i, pressure switch I01 now in closed position due to the pressure in the straight-air pipe IOI having exceeded five pounds per square inch, and a wire I22 to the negative terminal of the battery I I0.

The magnet valve device I00 is accordingly operated to rapidly vent fluid under pressure from the brake cylinder I00, thereby causing a rapid reduction in the degree of application of the brakes associated with the slipping car wheels.

Due to the rapid reduction in the degree of application of the brakes associated with the slipping wheels, the wheels promptly cease to decelerate and begin to accelerate back toward a speed corresponding to car speed without actually reducing to a locked or sliding condition.

When the fly-wheel I5 rotatively over-runs the shaft I2, the instantaneous differential in the rotational speeds of the two centrifuges I0 and I9 is immediately effective to shift the collar 9i so as to cause closure of the switch Bl. Switch 00 is effective, when closed, to establish a circuit for energizing the magnet windings II of the clutch release magnet device II. This circuit extends from positive terminal of the battery I I8, by way of the wire IIO, switch 04 and a wire I23 to the terminal post 10, thence by way of the wire 16 including the serially-connected magnet windings II to the terminal post I0, thence by way of wire I2I which is connected'to the terminal post 10, the pressure switch I01 and wire I22 to the negative terminal of the battery H8.

The magnet windings II of the magnet device II are thus energized substantially at the time that the spider member SI of the clutch device It is shifted axially in the righthand direction due to the fly-wheel I over-running the shaft I2. Consequently, the magnet device I! is eifective to maintain the spider member 3| displaced in its right-hand position to prevent the return of roller 33 into engagement with the notch 31 in annular cam 38 on the fly-wheel Ii.

The fly-wheel I5 is thus free to rotatively decelerate at a rate different from the rate of rotative deceleration of the shaft I2. The rate at which fly-wheel I5 decelerates is determined partly by the braking eifect exerted by brake shoe 36 and partly by the friction between the balls 88 on the ends of the bell crank levers 86 of the centrifuge I9 with the sliding collar 9|. The rate of deceleration of fly-wheel I5 is designed to correspond substantially to the normal rate of retardation of the car. Thus, the fly-wheel I5 continues to rotate at a speed corresponding to the speed of the car, whereas the shaft I2 rotates at a speed corresponding to the rotational speed of the individual wheel and axle unit 24.

As long as the wheel and axle unit 24 rotates at a speed substantially less than that of the flywheel I5, the diiierential force exerted by the two centrifuges I8 and I9 on the sliding collar BI is suillcient to maintain the switch 64 in closed position, thereby maintaining the magnet winding II of the magnet device I'I energized and the spider member 3| of the switch device It in its right-hand or disconnecting position. In its disconnecting position the clutch spider member SI maintains switch 51 in its closed position, thereby maintaining the magnet winding II3 of the magnet valve device I06 continuously energized so as to cause the venting of fluid under pressure from the brake cylinder I04 to continue during such interval of time.

When the slipping wheels have accelerated substantially back to a speed corresponding to car speed and, thus to the rotational speed of the flywheel I5, the forces exerted on collar 9| by centrifuges I8 and I9 are again balanced. In such case the resiliency of the contact fingers of switch 64 causes the sleeve 62 to be shifted in the left- I hand direction sufliciently to effect disengagement of the contact fingers of the switch 64. The switch 64 is thus opened and interrupts the circuit for energizing the magnet windings II of the magnet device II. The magnetic contraction of the magnet device I! for the clutch spider member 3| is thus removed and the biasing spring 39 accordingly restores the clutch spider member 3| into engagement with the cam 38 on the fly-wheel IS. The roller 33 may not immediately reengage in the notch 31 of the cam 30 but-it will do so when it again becomes aligned with the notch as a rerection suillciently to effect separation of the contact fingers of the switch 61. Opening of the switch 51 effects interruption of th circuit energizing the magnet winding III of the magnet valve device I06.

Magnet valve device I06 is accordingly restored to its normal position, in which it is shown, thereby re-establishing communication through. the branch pipe I05 from straight-air pipe IOI to the brake cylinder I04. Fluid under pressure is thus resupplied from the straight-air pipe IM to the brake cylinder I04 to effect a reapplication of the brakes on the corresponding wheels.

The supply of fluid under pressure from straight air pipe IOI to the brake cylinder I04 tends to reduce the fluid pressure in straight-air pipe IOI,

but as previously mentioned, the pressure-maintaining feature of the brake valve I02 is effective to cause fluid under pressure to be supplied to the straight-air pipe IOI to maintain a pressure slipping of the wheels and the above operation is again repeated so that at no time are the wheels permitted to decelerate to a locked or sliding condition.

Various expedients have been resorted to for the purpose of controlling the rate .at which fluid under pressure is resupplied to the brake cylinder I04, following slipping of the wheels, in order to minimize the possibility of repeated wheel slip cycles. It will be understood that I contemplate the application of my control device II in a fluid pressure brake equipment of such type. I have therefore omitted details of such features.

When the car comes to a complete stop, the switch 64 is always restoredto, its open position because the balancing of the forces on sliding collar SI as a result of the non-rotation of the centrifuges I8 and I9 renders the bias on one of the contact fingers of the switch free to separate the contact fingers of the switch. The magnet winding of the magnet device I'l thus always deenergized in response to stopping of the car so as to permit restoration of the clutch spider member 3I into locking engagement with the fly-wheel I5. The switch 51 is thus correspondingly always restored to its open position to effect deenergization of the magnet winding II3 of the magnet valve device I08. In any event, fluid under pressure is always resupplied to the brake cylinder I04 when the car comes to a complete stop so as to maintain the brakes applied.

When the operator desires to again proceed under power, he first releases the brakes merely by restoring the brake valve handle mm to its brake release position. Fluid under perssure in the straight-air pipe IM and in-the brake cylinder I04 is thus vented to atmosphere through the portand pipe I I0 at the brake; valve I02 and the brakes are accordingly completely released.

vWhen the pressure inthe straight-air pipe IOI r duces below five pounds per square inch, the pressure switch I0! is restored to its open position, thereby interrupting the. circuit of the magnet windings II of the magnet device ll and that of magnet winding III of the magnet valve device Ill. Possible energization thereof in response to an abnormal rate of acceleration of the car wheels, such as might occur if the car wheels are driving wheels. is thus prevented.

It will be understood that the control device II is responsive to an abnormal rate of acceleration of the car wheels as well as an abnormal rate of deceleration of the car wheels. I have not illustrated the manner in which the control device Il may be utilized to indicate an abnormal rate of acceleration but it will be apparent from the fact that the movement of the sleeve ll effected in response to acceleration will be opposite to that occurring during deceleration that the only change required is to reverse the position of the switch lI so that it is closed in response to movement of the sleeve ll in the left-hand direction instead of the right-hand direction.

Description of second embodiment employed in the first embodiment.

The control device shown in Figure 4, hereinafter designatedcontrol device Ila, comprises a base II and pedestals II for supporting a drive shaft Ila driven through bevel gears ll and ll in the same manner as in the first embodiment. A fly-wheel Ila having a relatively long hub is rotatively mounted on the shaft Ila and carries a centrifuge devic Ila.

I A centrifuge device Ila is carried by and fixed to the shaft Ila for rotation therewith.

A cluteh device Ila is provided for coupling the flywheel Ila to the shaft Ila. The clutch device Ila comprises a spider member Ila splined or keyed to the shaft Ila in a manner permitting axial movement thereof'on the shaft while fixed thereon for rotation with the shaft at all times. The spider member Ila carries a conical roller IIa that cooperates with a conical cam IIa, having a shallow V-shaped notch IIa therein, formed at the end of the hub of the flywheel Ila.

A counter-balancing weight Ila is secured to the spider member Ila in diametrically opposite relation to the roller In for dynamically balancing the spider member.

A coiled spring Ila, disposed in concentric surrounding relation to the shaft Ila, acts to urge the spider member Ila in the left-hand direction to cause the roller III: to engage in notch I'Ia, thereby locking the iiy-wheel Ila to the shaft Ila. The strength of spring Ila is such as to cause the fiy-wheel Ila and shaft Ila to rotate together until such time as the shaft Ila changes its rotational speed, that is either accelerates or decelerates, at a rate exceeding a certain rate.

Secured to the spider member Ila is a cylindrical member III which surrounds the shaft Ila in concentric relation. The member III carries at the outer end thereof a thrust bearing lIl.

Formed on or attached to the cylindrical member III adjacent theouter end thereof is an inwardly extending radial flange III havinga friction member III secured to one face thereof and effective to engage the radial rear surface of the cam Ila on the hub of the fiy-wheel Ila when the spider member Ila is shifted in the righthand direction sufficiently to disenl ge the roller IIa from the cam. A braking action is accordingly produced on the fly-wheel Ila to cause it to rotatively decelerate at a rate corresponding substantially to the normal maximum rate of retardation of a car, such as four or five miles per hour p r second.

In a manner similar to the clutch spider member of the first embodiment, the spider member Ila of the present embodiment is connected to a piston Ila operating in the bore Ila of the shaft Ila by a screw or pin I'Ia that extends through a suitable slot in the wall of the shaft Ila. The piston Ila has a stem Ila that extends through the bore and projects out of the left-hand open end thereof, a suitable guide bushing III removabb fixed in the bore Ila serving to support the end of the stem Ila.

InterpOsed between the piston Ila and the end of the bore Ila in the shaft Ila is a coil spring III which assists spring Ila in restoring the piston Ila to its normal position and also prevents chattering of the piston on the pin Ila.

The stem Ila of the piston Ila is effective to operate a switch l'l, corresponding to the switch II in the first embodiment, which functions in exactly the same manner.

The centrifuge device Ila comprises a hub portion having two oppositely extending curved arms terminating in yokes in which bell-crank levers Ila are pivotally mounted on pins Ila. A weight I1 is fixed on the outer end of one of the arms of each of the levers and the end of the other arm is of ball-shape and engages in an annular groove III provided at one end of the spider member Ila of the clutch Ila. It will thus be apparent that upon rotation of the shaft Ila, the centrifugal force on the weights I1 is effective to urge the.

spider member Ila in the left-hand direction to assist the spring Ila in maintaining the cooperative engagement of roller IIa with the notch IIa in the cam Ila on fly-wheel Ila.

The centrifuge device Ila carried by the flywheel Ila comprises a plurality of bell-crank levers Ila, each pivotally mounted on a pin II in the corresponding yoke brackets Ila formed on or attached to the rim of thefly-wheel Ila. A weight I1 is attached to the outer end of one arm of eachof the bell-crank levers Ila and the outer end of the other arm of each lever is of ball-shape and engages the outer surface of the thrust bearing Ill.

The centrifugal force on the weights ll of centrifuge device Ila is accordingly effective to exert a force urging the spider member Ila of the clutch device Ila in the right-hand direction in opposition to the force exerted by the centrifuge device Ila. The nature of the thrust bearing III is such that friction between the bell-crank levers Ila and the cylindrical member III carried on the spider member Ila, which would otherwise result due to the relative rotation of the fly-wheel and the shaft I la, is negligible.

Operation of second embodiment When the shaft Ila rotates at a constant speed, the centrifugal forces exerted by the two centrifuges Ila and Ila on the spider member Ila are equal and opposite and spring Ila is effective to urge the spider member Ila in the left-hand direction so as to cause the roller Ila to engage in looking relation in the cam notch IIa on the hub of the fly-wheel Ila thereby locking thefly-wheei to the shaft and causing it to rotate at the same speed as the shaft.

When the shaft l2a rotatively deceierates, the fly-wheel lia tends to overrun the shaft 12a due to its inertia or momentum. The rate of rotative deceleration of shaft l2a at which the inertia force of momentum of the fly-wheel lid is sufficient to cause axial movement of the spider lla of'the clutch device Na in the right-hand direction will depend upon the speed of the shaft Ha. This is so because in order to shift the spider 3| a in the right-hand direction it is necessary to move the weights 8! of the centrifuge device I811 radially inward. The centrifugal force acting to move the in order to cause shifting of the clutch spider member 3: in the right-hand direction in response to the momentum of the fly-wheel l5a because the force of momentum of the fly-wheel is proportional to the rate of change of speed of the fly-wheel.

Assuming, however, that the shaft l2a does rotatively decelerate at a suificient rate to cause shifting of the clutch spider member 31a in the right-hand direction in opposition to the spring 39a and the centrifugal force on the weights 81 of the centrifuge device l8a sufficiently to disengage the roller 33a from the notch 31a in the cam 38:: on the hub of the fly-wheel i542, it will be seen that instantaneously the rotational speed of the flywheel exceeds that of the shaft I2a because it is unlocked from the shaft. Moreover, since the radius of rotation of the weights 81 of the centrifuge l8a has been decreased while that ,of the weight 81 of the centrifuge device I911 has not been measurably decreased, it will be seen that once the fly-wheel I50: is unlocked from the shaft l2a, the differential between the centrifugal force on the weights 8? of the centrifuge la and the centrifugal force on the weights 8! of the centrifuge i8a becomes effective to hold the spider member 3m displaced in its right-hand position in opposition to the force of spring 39a. This differential increases asthe disparity in the rotational speeds of the fly-wheel and the shaft increases, as it does during the decelerating portion of the slipping cycle of a vehicle wheel.

With the roller 33a of the clutch device lia thus held out of engagement with the cam 38a on the hub of the fly-wheel, the fly-wheel has a braking effect exerted thereon by the engagement of the friction surface E34 on the flange I33 of the cylindrical member l3i. This braking effect is such as to cause the fiy-wheel a to be rotatively decelerated substantially in accordance with the rate of retardation of the car or vehicle so that the instantaneous speed of the fly-wheel corresponds substantially to the instantaneous speed of the car.

When the spider member 3 la of the clutch device |6a is shifted in the right-hand direction, switch 51 is closed to effect energization of the magnet winding N3 of magnet valve I06 just as in the first embodiment. Thus, assuming that a brake application has been effected, the fluid under pressure is released from the brake cylinder I04 just as in the operation of the first embodi ment.

Due to'the rapid release of reduction in the degree of application of the brakes associated with the slipping wheels, shaft lIa promptlyceases to decelerate and begins to accelerate back toward a speed corresponding to car speed. As long as the shaft Ha rotates at a speed sumciently less than the speed of rotation of the fly-wheel Ila, the differential of'the centrifugal forces exerted by thetwo centrifuges is effective to maintain the roller Ila of the clutch device lia displaced in its right-hand position, thereby causing the switch 51 to be maintained closed and the reduction in the degree of application of the brakes to be continued.

Whenthe slipping vehicle wheels have been restored substantially to vehicle speed, however, the differential between, the forces of the two centrifuges 13a and Isa-is insufficient to overcome the springs 39!; and I3! and the springs therefore shift the spider member 3 la in the left-hand direction to effect reengagement of the 'roller 33a in the notch 31a of the cam 38a on the hub of the fly-wheel. The fly-wheel l5a is thus again locked to the shaft 12a and rotates at the same speed. In such case, therefore, the two centrifuges I81: and Isa again exert equal and opposite forces on the spider member 3 l a.

It will be apparent that if a braking effect were not exerted on the fly-wheel lia, it would continue to rotate at a speed faster than that corresponding to car speed except as it would decelerate gradually due to friction in the bearings journaling it to the shaft l2a. In such case, the restoration of the spider 3|a to its normal lefthand position would be delayed until such time as the differential in the centrifugal forces of the two centrifuges "la and Illa diminished sufficiently so as to permit restoration of the spider member Me by the springs 39a and I31. It is desirable, therefore, to exert a braking effect on the fly-wheel |5a so that, at the time the slipping wheels are restored to car speed, the flywheel |5a is rotating instantaneously at a speed corresponding to car speed, thereby insuring the prompt opening of the switch 51 and consequent termination of the reduction of pressure in the brake cylinder I04.

In view of the complete description of the operation of the control device II in connection with the fluid pressure brake system shown in Figure 1, it is believed unnecessary to further describe the operation of the control device Ha of Figure 4.

Having now described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A control device comprising a shaft rotatable at different speeds, a fly-wheel, a clutch device establishing a connection whereby rotation of the shaft causes rotation of the fly-wheel and permitting rotation of the fly-wheel and shaft at different relative speeds differing in degree according to the rate of change of rotational speed'of the shaft, means responsive to the speed of the shaft, means responsive to the speed of the fly-wheel, and control means operatively controlled by said two speed responsive means.

2. A control device comprising a shaft rotatable at different speeds, a fly-wheel, a clutch device establishing a driving connection whereby said fly-wheel is rotated upon rotation of the shaft and permitting rotation of the fly-wheel at speeds differing in degree with respect to the speed of the shaft dependent upon the rate of change of at all times in accordance with the rotational speeds of the shaft, centrifugal means rotatable at all times in accordance with the rotational speed of the fly-wheel. and control means operatively responsive according to the relation of the forces exerted by said two centrifugal means.

3. A control device comprising a shaft rotatable at different speeds, a fly-wheel, a clutch device establishing a driving connection whereby said iiy-wheel is rotated upon rotation of the shaft and permitting rotation of the fly-wheel at speeds differing in degree with respect to the speed of the shaft dependent upon the rate of change of speed of the shaft, centrifugal means rotatable at all times in accordance with the rotational speed of the shaft, centrifugal means rotatable at all times in accordance with the rotational speed of the fly-wheel, and control means operatively responsive to a predetermined differential in the forces exerted by said two centrifugal means.

4, A control device comprising a shaft rotatable at diflerent speeds, a fly-wheel, a clutch device including a movable member effective in one position to connect said fly-wheel to said shaft for rotation with said shaft and having a different position in which said fly-wheel is disconnected from said shaft, said clutch member being moved to a position disconnecting the fly-wheel from the shaft in response to the change in the rotational speed of the shaft at a rate exceeding a certain rate, means effective when the fly-wheel is disconnected from the shaft as long a the differential between the speeds of the shaft and fly-wheel exceeds a certain amount for maintaining said clutch member in a position disconnecting the fly-wheel from the shaft, and control means operatively responsive to movement of said clutch member. 5. A control device comprising a shaft rotatable at different speeds, a fly-wheel, a clutch device including a movable clutch member effective in one position to connect said fly-wheel to said shaft for rotation with said shaft and having a different tion in which said fly-wheel is disconnected rom said shaft, said clutch member being moved to a position disconnecting the fly-wheel from the shaft in response to the change in the rotational speed of the shaft at a rate exceeding a certain rate, centrifugal means rotatable at all times in accordance with the rotational speed of the shaft, centrifugal means rotatable at all times in accordance with the rotational speed of the fly-wheel, effective as long as the differential in the forces exerted by the two centrifugal means ex- (seeds a certain amount for maintaining said clutch member in a pomtion disconnecting the fly-wheel from the shaft, and control means operatively responsive to movement of said clutch member. j"8. A control device comprising'a shaft rotatable it" different speeds, a fly-wheel, a clutch device including a movable clutch member effective in use position to connect said ny-wheel to said shaft for rotation with said shaft and having a different position in which said fly-wheel is disconnected from said shaft, said clutch member being moved to a position disconnecting the fly-wheel from the shaft in response to the change in the rotational speed of the shaft at a rate exceeding a certain rate, electro-responsive means effective, when energised, to maintain said clutch member in its position disconnecting the fly-wheel from the shaft, means eifectiveas long as the differential in the speeds of the fly-wheel and the shaft exceeds a certain amount for maintaining said elecas'rasso tro-responsive means energized, and control means operatively responsive to movement of said clutch member.

7. A control device comprising a shaft rotatable atdiiferent speeds, a flywheel, a clutch device including a movable clutch member eflective in one position to connect said fly-wheel to said shaft for rotation with said shaft and having a different position in which said fly-wheel is disconected from said shaft, said clutch member being moved to a position disconnecting the flywheel from the shaft in response to the change in therotational speed of the shaft at a rate exceeding a certain rate, electro-magnetic means effective, while energized, to maintain the clutch member in its position disconnecting the fly-wheel from the shaft, centrifugal means rotatable at all times in accordance with the speed of the shaft, centrifugal means rotatable at all times in accordance with the speed of the fly-wheel, and means subject in opposing relation to the forces exerted by said two centrifugal means and effective to cause energization of said elctro-magnetic means.

as long as the differential in the speeds of the dywheel and shaft exceeds a certain amount, and control means operatively responsive to movement of the clutch member.

8. A control device comprising a shaft rotatable at different speeds, a fly-wheel rotatively mounted on said shaft, a clutch member fixed on said shaft for rotation therewith at all times and axially shiftable into and out of engagement with said fly-wheel to connect or disconnect said 17- wheel from said shaft, resilient means maintaining said clutch member in a position connecting the fly-wheel to the shaft as long as the shaft does not change its speed at a rate exceeding a certain rate and effective to yieldlngly permit movement of the clutch member to a position disconnecting the fly-wheel from the shaft when the shaft r04 tatively changes its speed of rotation at a rate exceeding said certain rate, means operatively responsive to a predetermined differential in the rotational speeds of the fly-wheel and the shaft for maintaining said clutch member in a position disconnecting the fly-wheel from the shaft once the clutch member is moved to the-disconnecting position, and control means operatively responsive to movement of said clutch member.

9. A control device comprising a shaft rotatable at different speeds, a fly-wheel rotatively mounted on said shaft, a clutch member fixed on said shaft for rotation therewith at all times and axially shiftable into and out of engagement with said fly-wheel to connect or disconnect said fiywheel from said shaft, resilient means maintaining said clutch member in a position connecting the fly-wheel to the shaft as long as the shaft does not change its speed at a rate exceeding a certain rate and effective .to yieldingiy permit movement ofthe clutch member to a position disconnecting the fly-wheel from the shaft when the shaft rotatively changes its speed of rotation at a rate exceeding said certain rate, non-rotative electromagnetic means associated with said clutch member and effective, while energized, after the clutch member is moved to its position disconnecting the fly-wheel from the shaft to maintain said clutch member in its disconnecting position, means operativeiy responsive to a predetermined differential in the rotational speeds of the fly-wheel and shaft for maintaining said electro-magnetic means energized, and control means operativalr responsive to movement of said clutch member.

76 10. A control. device comprising a shaft rotatable at different speeds, a fly-wheel rotatively mounted on said shaft, a clutch member on said shaft for rotation therewith at all times and axially shiftable into and out of engagement with said fly-wheel to connect or disconnect said flywheel from said shaft, resilient means maintaining said clutch member in a position connecting the fly-wheel to the shaft as long as the shaft does not change its speed at a rate exceeding a certain rate and effective to yieldingly permit movement of the clutch member to a position disconnecting the fly-wheel from the shaft when the shaft rotatively changes its speed ofrotation at a rate exceeding said certain rate, electro-magnetic means associated with said clutch member and effective, while energized, after the clutch member is shifted axially to its position disconnecting the fly-wheel from the shaft for maintaining the clutch member in its disconnecting position, centrifuge means carried by shaft, centrifuge means carried by said fly-wheel, means operatively responsive to a predetermined differential in the forces exerted by the two centrifuge means for effecting energization of said electro-magnetic means, and control means operatively responsive to axial movement of said clutch member.

11. A control device comprising a shaft rotatable at different speeds, a fly-wheel, clutch member for connecting and disconnecting said flywheel from said shaft, resilient means effective to urge said clutch member in a direction to connect the fly-wheel to the shaft, means for exerting opposing forces on said clutch member corresponding respectively to the rotational speeds of the shaft and fiy-wheel, and control means operatively responsive to the movement of said clutch member.

12. A control device comprising a shaft rotatable at different speeds, a fly-wheel, clutch member for connecting and disconnecting said flywheel from said shaft, resilient means efiective to urge said clutch member in a direction to connect the fly-wheel to the shaft, acentrifuge device rotatable at all times in accordanc with the rotational speed of the shaft for exerting a corresponding force on the clutch member urging it in a direction to connect the fly-wheel to shaft, a centrifuge device rotatable at all times in accordance with the rotational speed of the flywheel and exerting a force on said clutch member in opposition to the force of the first said centrifuge device whereby to maintain the clutch member in a position disconnecting the fly-wheel from the shaft as long as the differential in the forces exerted by the two centrifuge devices exceeds a certain amount, and control means operatively responsive to movement of the clutch member.

13. A control device comprising a shaft rotatableat different speeds, a fly-wheel, a clutch member effective in one position to connect said fly-wheel to said shaft and shiftable to a different position in which said fly-wheel is disconnected from said shaft, resilient means urging the clutch member toward the position in which it connects the fly-wheel to the shaft, a centrifuge device carried by said shaft and effective to exert a force on said clutch member urging it toward the posi-- tion in which it connects the fly-wheel to the shaft, a centrifuge device carried by said fly-wheel and effective to exert a force on said clutch member in opposition to the force of the first said centrifuge device, said fly-wheel being so constructed and arranged that the inertia 'of the flywheel is effective upon a change in the rotational speed of the shaft to exert a force on said clutch member in a direction to disconnect the fly-wheel from the shaft, the unbalanced forces exerted by the two centrifuge devices being effective to maintain said clutch member in a position disconnecting the fly-wheel from the shaft as long as the rotational speeds of the fly-wheel and shaft differ relatively by more than a certain amount, and control means operatively responsive to movement of said clutch member.

14. A control device comprising a shaft rotatable at different speeds, a fly-wheel, a clutch device for connecting said fly-wheel to and disconnecting said fly-wheel from said shaft, means responsive to the. inertia of the fly-wheel upon a change in the rotational speed of the shaft for operating said clutch device to disconnect said fly-wheel from said shaft, means effective upon relative rotational movement of the fly-wheel and shaft to exert a braking effect on said fly-wheel, means effective in response to a predetermined differential in the rotational speeds of the flywheel and shaft to maintain the clutch device in a position disconnecting the fly-wheel from the shaft, and control means actuated from a normal position to an operated position in response to rotational movement of the fly-wheel relative to said shaft.

15. A control device comprising a shaft rotatableat different speeds, a, fly-wheel, a clutch member rotatable with the shaft and shiftable axially on said shaft into and out of a position establishing a driving connection between the shaft and the fly-wheel, said fly-wheel cooperating with said clutch member in such a manner as to shift the clutch member to position disconnecting the fly-wheel from the shaft when the shaft changes its speed of rotation at a rate exceeding a certain rate, means carried by the clutch member and frictionally engaging the fly-wheel to exert a braking effect thereon upon relative rotational movement of the fly-wheel and shaft, means responsive to a predetermined differential in the rotational speeds of the fly-wheel and shaft for maintaining said clutch member in a position disconnecting the fly-wheel from the shaft, and control means operatively responsive to the axial movement of said clutch member.

16. A control device comprising a shaft rotatable at different speeds, a fly-wheel, a clutch device establishing. a driving connection from the shaft to the fly-wheel and effective to permit rotational movement of the fly-wheel with respect to the shaft, means for exerting a braking effect on the fly-wheel when the fly-wheel rotates with respect to said shaft, and control means operatively responsive to a predetermined differential in the rotational speeds of the fly-wheel and shaft.

17. In a vehicle brake control system of the type having brake control means operative during a brake application to effect a reduction in the degree of application of the brakes associated with a wheel of the vehicle, the combination of a fly-wheel, clutch means providing a driving connection between the fly-wheel and the vehicle wheel and effective to permit rotation of the flywheel at a speed higher than that of said wheel when the wheel rotatively decelerates at a rate exceeding a certain'rate, a control device actuated from a normal to an operated condition in response to the rotational movement of the flywheel with respect to the said wheel for initiating tion between the fly-wheel and the vehicle wheel and effective to permit rotation of the fly-wheel at a speed higher than that of said wheel when the wheel rotatively-decelerates at a rate exceeding a certain rate, a control device actuated from a normal to an operated condition in response to the rotational movement of the i'Lv-wheel with respect to the said wheel for initiating operation of said brake control means, and speed differential responsive means effective as long as the differential in the rotational speeds of the fly-wheel and the said wheel exceeds a certain amount for; causing said control device to be maintained in its operated condition.

19. In a vehicle brake control system of the type having means operative during a brake application to effect a reduction in the degree of application of the brakes associated with a wheel of-the vehicle, the combination of a fly-wheel,

clutch means providing a driving connection between the fly-wheel and the vehicle wheel and effective to permit rotation of the fly-wheel at a speed higher than that of said wheel when the wheel rotatively deoelerates at a rate exceeding a certain rate, a control device actuated from 5 a normal to an operated condition in response to'the rotational movement of the fly-wheel with respect to the said wheel for initiating operation of said brake control means. a first centrifuge device rotatable at all times inaccordance with the'rotational speed of the vehicle wheel. a second centrifugal device rotatable at all times-in accordance with the rotational speed of the flywheel, and means responsive to a predetermined diflerential between the forces exerted by said centrifuge devices for causing said control device to remain in its operated condition. 1

20. In a vehiclebrake control equipment of the type having a magnet-valve device eflective when energized during -a brake application to effect a reduction in the degree of application of. thebrakesassociated with a wheel of the vehicle, the combination of a fly-wheel, a clutch member rotatable at all times according to the rotational speed of the vehicle wheehresilient means biasing said clutch-member into engage- ,ment-with said fly-wheel to establish a (kl-V1118 connection between the vehicle wheel and the ily-wheel and yieldingly responsive to the inertia of the fly- -wheel to permit movement of the clutch member -.to disconnect the fly-wheel from the vehicle .wheel, switch means operatively responsive to the movement of the clutch member when disconnecting the flywheel from the vehicle wheel to cause energiaation of said magnet valve means, electro-magnetic means effective when energized to maintain said -clutch member in a .position disconnecting said fly- 'wheel from said vehicle wheel, and means responsive to a predetermined differential in the rotational speeds of the fly-wheel and the vehicle wheel for maintaining said electro-magnetic means energised.

21. Inavehiclebrakecontroi equ pment ofthe type having a magnet valve device effective when energised during a brake application to elect a reduction in the degree of application of the brakes associated with a wheel of the vehicle, the combination of a fly-wheel, a clutch member rotatable at all times according to the rotational speed of the vehicle wheel, resilient means biasing said clutch member into engagement with said fly-wheel to establish a driving connection between the vehicle wheel and the fly-wheel and yieldingly responsive to the inertia of the flywheel to permit movement of the clutch member to disconnect the fly-wheel from the vehicle wheel, switch means operatively responsive to the movement of the clutch member when disconnecting the fly-wheel from the vehicle wheel to cause energization of said magnet valve means, electro-magnetic means effective when ener i e to maintain said clutch member in a position disconnecting said fly-wheel from said vehicle wheel, a first centrifuge device rotatable at all times according to the rotational speed of the vehicle wheel, a second centrifuge device rotatable at all times in accordance with the rotational speed of the fly-wheel, and switch means operatively responsive to a predetermined differential in the forces exerted by said two centrifuge devices for causing energization of electro-magnetic means.

' 22. A control device comprising a shaft rotatable at different speeds, a fly-wheel, a clutch device normally associating the fly-wheel with the shaft in such a manner as to cause the fly-wheel and shaft to rotate together at the same speed. means responsive to a change in the rotational speed of the shaft at a rate exceeding a certain rate for effecting operation of the clutch device in a manner to free the fly-wheel for rotation at a speed different from-the speed of rotation of the shaft, and control means operatively responslve to a certain differential in the rotational speeds of the fly-wheel and the shaft for controlling the clutch device in a manner to maintain the fly-wheel freely rotatable with respect to and at a different speed than said shaft.

23. A control device comprising a shaft rotatable at different speeds, a fly-wheel, a clutch device normally associating said fly-wheel with the shaft in a manner to cause rotation of the fly-wheel and-shaft'together at the same speed, means responsive to a change in the rotational speed of the shaftat a rate exceeding a certain rate for effecting operation of the clutch device to free the fly-wheel for rotation at a different speed than said shaft, means responsive to the speed of the shaft, means responsive to the speed of the fly-wheel, and control means operatively controlled by the cooperative action of said two speed responsive means forcontrolling the said clutch device in a manner to maintain the fly-wheel freely rotatable with respect to and at a diflerent speed than the shaft as long as there is a certain diflerential between the speed of the fly-wheel and that of the shaft.

, CLYDE C. FARMER. 

